Currently, a display apparatus such as a liquid crystal television uses an IC board to process display signals. Various data processing chips are integrated on the IC board, and the data processing chips are connected through internal interfaces. During the normal operation of the IC circuit board, various input signals are received by an external connection interface CN1 from external signal sources.
In practical applications, a certain module in the IC board usually needs to be tested. In this case, a certain internal interface will be plugged into an external test circuit, and external test signals are acquired or input into the module to be tested via the internal interface.